Electromotive MII https://www.metrology.net/wiki/testprocess-measure-voltage-ac/ Input Name of the UUT Connecting Point The Frequency of the Referece Voltage A test process that measures the amplitude-response difference between two sinusoidal AC sinewave signals at different frequencies while keeping the source voltage level constant. The two measured values are compared, the results can be expressed as (e.g.) straight ratio, dB or percent of change. These two signals are often used when calibrating flatness of a device.